fix typo

doc/user_guide/Explorer.ipynb

@@ -50,7 +50,7 @@
    "id": "2f572b55-5002-4b81-9c92-6a2b56e2cde2",
    "metadata": {},
    "source": [
-    "For an explorer to be displayed in a notebook you need to load the hvPlot extension, which happens automatically when you execute an import like `import hvplot.pandas`. You could also just run `hvplot.extension('bokeh')`. If instead of building Bokeh plots you would rather build Matplotlib or Plotly plots, simply execute once `hvplot.extension('matplotlib')` or `hvplot.extension('matplotlib')` before displaying the explorer."
+    "For an explorer to be displayed in a notebook you need to load the hvPlot extension, which happens automatically when you execute an import like `import hvplot.pandas`. You could also just run `hvplot.extension('bokeh')`. If instead of building Bokeh plots you would rather build Matplotlib or Plotly plots, simply execute once `hvplot.extension('plotly')` or `hvplot.extension('matplotlib')` before displaying the explorer."
    ]
   },
   {